Pardon me for enjoying this discussion. I remember these issues well. Although I raised two daughters, what mostly tickles me is memories of my own adolescence. I was a very tiny and a late bloomer, and at eleven years old I really, really wanted a bra - but had absolutely NOTHING to hold one up! My poor parents could barely keep a straight face... And unfortunately, although I can laugh about it now, what I mostly remember was that my parents LAUGHED at me... SO, my first bit of advice is - this is serious business to our daughters... try hard to respect that!
Here's something I tried with my oldest daughter, who had the baby-finest strawberry blond hair on her legs. Although she could "see" this hair, it was the same baby hair she'd always had and really did not warrant shaving. I told her that we would try shaving a small section of her leg, so that she could see how it felt when it grew back in. Then if she still really WANTED to shave it, I would let her (again, a matter of taking her seriously). So, you know, it grew back in and felt (of course) coarse and yucky. But you know what? She still wanted to shave it, so I taught her how to use the razor, supervised her, bit my tongue, etc. After a couple of weeks of this, she had enough of it and gave it up! Mission accomplished until she got "real" grown-up hair.
I don't think there's a right or wrong. I've heard some mothers say that if they let their kids do all the "grown up stuff" now, that when they do grow up, there won't be any exciting "rights of passage" and they will have to find "other stuff" to do, stuff that we parents probably wouldn't like. I think there's probably something to that. I guess each situation and each girl is unique. I'd probably have to weigh out her actual discomfort, my actual discomfort, and your personal values about "growing up too fast."
Good luck to you, and know that we're all in there with you - wishing our little girls would stay little just a little while longer!
S.